1. Field of the Invention
This invention relates to the intake system for internal combustion engines in which the fuel-air mixture is heated. This invention is more specifically directed to the intake for internal combustion engines wherein a stream of hot air is injected and mixed with the fuel-air mixture to heat said fuel-air mixture and in part turbulence to the fuel-air mixture for better combustion.
2. Description of the Prior Art
It is well known that the fuel efficiency of an internal combustion engine is improved by heating the fuel-air mixture prior to combustion. Heating can be accomplished by inserting a device in the path of the fuel-air mixture which acts as a heat transfer means for heating the fuel-air mixture. For example, the following patents described various devices used to preheat the fuel-gas mixture:
U.S. Pat. Nos. 3,224,425, 35,300,844, 4,137,881, 596,887, 4,044,742, 3,640,256, 2,018,122, 4,009,701, 1,321,952, 2,254,634 and 3,294,381.
It is also well known that an internal combustion engine can be adapted to precondition the fuel-air mixture prior to combustion in the cylinders by directly introducing into the mixture the hot products of combustion from the exhaust manifold. An example of said art is found in U.S. Pat. No. 1,815,432.
It is further known that heated air can be injected directly into the intake manifold. For example, U.S. Pat. No. 4,167,166 teaches the injection of pressurized air in the manifold. However, this device is not adapted to provide thorough mixing of the heated air with the air-fuel mixture.
This invention has as an object the introduction of hot air to precondition the fuel-air mixture. This invention further has an object to introduce heated air into the air-fuel mixture in a manner to provide complete mixing of the heated air and the air-fuel mixture. To accomplish this end, preferably, heated air is introduced into the carburetor at a point below the throttle valve of the carburetor and not more than two inches below the throttle valve. This invention has, as a further object, the introduction of a limited amount of hot air into the fuel-air mixture by means of a restriction in the tubing conveying the hot air. This restrictor permits the flow of a preferred amount of hot air into the mixture to vaporize and precondition the fuel-mixture for engines having up to 400 cu. inch displacement but any engine can utilize the device. It has been found that the use of my invention appreciably increases the performance of the engine in several respects:
1. If the engine is used in an automobile, the miles per gallon is appreciably increased from 10 to 50% or more depending upon size and age of the engine.
2. More complete combustion of the fuel is achieved which leads to longer spark plug life due to less carbon build-up on the spark plugs.